In vitro hyphal cell wall staining of the fungus Aspergillus fumigatus.Aspergillus fumigatus tdTomato is stained with the fluorophore coupled antibody JF5 Dylight650 and the nucleus with DAPI. The fungus was grown for 16h after conidia seeding. (By Djamschid Solouk)

PMA-induced NETosis of human neutrophils. 2-Photon imaging of NETosis events induced via PMA-stimulation. The extracellular traps are stained with Sytox-Orange, while the activation of neutrophils is indicated via the expression of CD66b on the cell surface. (By Anika Klingberg and Manuel Stecher)

Visualisation of NETs by bicoloured dSTORM. Human Neutrophils were stimulated with PMA for 3 hours at 37°C. Afterwards, the cells were fixed with 4% PFA. Histones H1 and Neutrophil Elastase were stained with antibodies. Consequently the MEA-buffer was added, which brought the fluochromes in a blinking state. (By Alexandra Brenzel and Jacqueline Heinen-Weiler)

Originals » The Catchup Mouse

What is the Catchup mouse?

The Catchup mouse is a novel animal model for highly neutrophil specific expression of the red fluorescent protein tdTomato. This specificity is achieved by modulation of the Ly6G (human homolog: CD177) locus, which is highly specific for neutrophil granulocytes in mice. Therefore, this mouse model not only allows intravital microscopy or flow cytometry of untouched and unstained neutrophils in various health and disease models, but, due to the features of the Cre-lox contruct, opens up the unique opportunity for a highly specific genetic modification of murine neutrophils. (For the original publication see: Hasenberg et al. Catchup: a mouse model for imaging-based tracking and modulation of neutrophil granulocytes)

How does the Catchup mouse work?

As Ly6G is a marker selectively expressed by murine neutrophils, it was considered a suitable target. The first step was the generation of a mouse line in which the first exon of Ly6g is replaced by a knock-in allele encoding the Cre recombinase (see also: Cre-lox system) and the fluorescent protein tdTomato separated by a self-splicing T2A peptide. (Figure 1) Heterozygous mice express both tdTomato and Ly6G, while homozygous mice lack Ly6G expression completely.
Figure 1. Catchup, a mouse model for the genetic manipulation of neutrophils. Targeting strategy for the generation of Catchup mice. Ex, exon.

For laboratories and institutes interested in our mouse line:

The Catchup mouse model is available for shipping from our institute in Essen, Germany. If you are interested in obtaining this mouse line for your research, do not hesitate to ask Prof. Dr. Matthias Gunzer (matthias.gunzer@uni-due.de) directly. He will refer you to the people responsible for mouse shipping, who will help you regarding all arising questions.